Sudden infant death syndrome (SIDS) occurs in young infants during a narrow time range that peaks at 3 months and extends over about two years from birth. It is relatively common (7,000 deaths in the United States per year). Usually it is defined in the negative: "The sudden death of any infant or young child which is unexpected in history and in which a thorough post-mortem examination fails to demonstrate an adequate cause for death".
SIDS is believed to have multiple causal mechanisms for which various theories have been forwarded. One potential cause of SIDS is the sudden cessation of ventilation (apnea; for a survey, see Thach B T, Apnea and the Sudden Infant Death Syndrome, Saunders N & Sullivan C, Eds., Lung Biology in: Health and Disease, Vol. 7/I, Marcel Dekker, New York 1994, p. 649-671. In most cases, life-threatening episodes of apnea in infants can be managed by stimulation or by artificial respiration provided apnea is detected at once and appropriate measures are taken immediately upon detection. Close surveillance of infants at risk thus is indicated.
Several factors identified in epidemiological studies of SIDS are associated with increased susceptibility of infants to infectious diseases, particularly upper respiratory tract infections. The period in which infants are at highest risk roughly corresponds to the period when maternal antibodies in the infant are decreasing while its immature immune system is not able to provide full compensation. The vast majority of SIDS-related deaths occur below the age of two years. Not only are breast-fed infants less vulnerable to infections but also less susceptible to SIDS. Many babies who died from SIDS had mild gastrointestinal tract infection shortly before death; IgA response of their duodenal mucosa was found to be significantly increased (Stoltenberg L et al., Pediatr. Res. 32 (1992) 372-375).
In the apnea hypothesis for SIDS, the cause of death is thought to be suffocation. The infant suddenly stops breathing. This might be caused, for instance, by acute upper airway obstruction, gastroesophageal reflux or abnormal cardiopulmonary control.
Means for identifying SIDS-prone infants are lacking. Close monitoring of infants identified being at SIDS risk can be expected to substantially reduce mortality. Pharmaceutical means for preventing SIDS in infants are lacking. Their possible use would require identification of infants at risk.